<!DOCTYPE html>
<html>
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <style>
    body {
      margin: 0px;
    }

    iframe {
      position: absolute;
      width: 200px;
      height: 200px;
      border: none;
      transform-origin: top left;
      transform: rotateZ(45deg);
    }

    div {
      position: absolute;
    }

    #clip1 {
      width: 300px;
      height: 100px;
      background-color: red;
      overflow: hidden;
    }

    </style>
  </head>
  <body>
    <div id="clip1">
      <iframe src="/cross-site/baz.com/title1.html"></iframe>
    </div>
  </body>
</html>
